Police officers must obtain a search warrant before snooping through the contents of a suspect’s cell phone, Ohio’s supreme court ruled on Tuesday.

The issue of whether mobile phones fall under US Fourth Amendment rights against unreasonable searches and seizures appears never to have been weighed by any other US state supreme court or the federal Supremes.

The Ohio court’s narrow, 4-3 majority decision in favor of Antwaun Smith reversed a ruling of the 2nd District Court of appeals. It determined that even the most humble of modern cell phones hold a sufficient wealth of personal data that it provides the device with a high expectation of privacy.

Smith was arrested on drug-related charges after responding to a call on his cell phone made by a crack cocaine user acting as a police informant.